A bulk material, rectangular in shape, composed of a multitude of individual small cells. It is produced in various lengths, widths, and thicknesses, and may have a finished surface or a rough (natural) surface. It is used for low temperature insulation, buoyancy, and also in the electrical, display, and novelty fields. Excludes CORE MATERIAL, CELLULAR, STRUCTURAL; CUSHIONING MATERIAL, PACKAGING; and INSERT, PACKAGING.